Answer:
The value of y is 21.
Explanation:
The formula of inversely proportional is y = k/x where k is a constant. So in order to find y, you first have to find the value of k by substituing x and y values into the formula :

Let y = -105,
Let x = -3,



We have already found k value. Next you have to find the value of y :

Let x = 15,

